Restrictions
This document describes the constraints and precautions of using the key functions of GaussDB(DWS).
After creating a GaussDB(DWS) cluster, you do not need to perform basic database O&M operations, such as HA and security patch installation. However, you need to pay attention to the following:
Specification and Performance Limits
Item |
Limit |
Description |
---|---|---|
Multi-AZ |
3 |
|
Storage |
|
|
Number of deployed CNs |
The value ranges from 3 to the number of cluster nodes. The maximum value is 20 and the default value is 3. |
In a large-scale cluster, you are advised to deploy multiple CNs. |
Maximum number of connections |
|
For details about CNs and DNs, see Logical Cluster Architecture. |
Quota Limits
Item |
Limit |
Description |
---|---|---|
Number of nodes |
256 |
The number of nodes in a new cluster cannot exceed the quota that can be used by a user or 256. If the node quota is insufficient, click Increase quota to submit a service ticket and apply for higher node quota. |
Tags |
Each cluster can have a maximum of 20 tags. |
For more information, see Overview. |
Snapshot storage space |
GaussDB(DWS) provides some free-of-charge storage space for you to store the snapshot data. |
However, if you use more space than the free-of-charge storage space, the exceeded part is charged according to OBS billing rules. For details, see the OBS pricing details. The amount of free space you have is equal to the total storage capacity of your cluster. This can be calculated by multiplying the storage capacity of a single node (standby node) by the number of nodes in the cluster. |
Retention period of automated backups |
The value ranges from 1 to 31 days. The default value is 7 days. |
The system deletes expired snapshots when the retention period ends. |
Naming Rules
Item |
Description |
---|---|
Cluster name |
Enter 4 to 64 characters. Only letters (case-insensitive), digits, hyphens (-), and underscores (_) are allowed. The name must start with a letter. |
Administrator account |
|
Role name |
The value must start with a letter and can contain a maximum of 63 characters, including letters, digits, and underscores (_). |
Username |
The value must start with a letter and can contain a maximum of 63 characters, including letters, digits, and underscores (_). |
Snapshot name |
The snapshot name must be 4 to 64 characters in length and start with a letter. It is case-insensitive and contains only letters, digits, hyphens (-), and underscores (_). |
Snapshot policy name |
The policy name must be unique, consist of 4 to 92 characters, and start with a letter. It is case-insensitive and can contain only letters, digits, hyphens (-), and underscores (_). |
Alarm rule name |
The rule name contains 6 to 64 characters and can contain only letters, digits, and slashes (/). |
DR name |
The DR name contains 4 to 64 case-insensitive characters and must start with a letter. It can contain only letters, digits, hyphens (-), and underscores (_). |
Restrictions on Basic Cluster Operations
Item |
Description |
---|---|
Binding a load balancer |
|
Adding or deleting a CN node |
|
Managing resource load |
|
Managing logical clusters |
|
Restarting a cluster |
A cluster cannot provide services during the restart. Therefore, before the restart, ensure that no task is running and all data is saved. If a cluster is processing transactional data, for example, importing data, querying data, creating snapshots, or restoring snapshots, files may be damaged or the cluster may fail to be restarted once the cluster is restarted. You are advised to stop all cluster tasks before restarting a cluster. |
Starting or stopping a cluster |
After the cluster is stopped, ECS basic resources (vCPUs and memory) are no longer reserved. When you start the service again, it may fail to be started due to insufficient resources. In this case, wait for a while and try again later. |
Restrictions on Cluster O&M Operations
Item |
Description |
---|---|
Scaling out a cluster |
|
Scaling in a cluster |
|
Performing elastic specification changes |
|
Performing classic specification changes |
|
Backing up and restoring a cluster |
|
Upgrading a cluster |
|
Managing DR tasks |
|
Managing logs |
|
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